I use a similar procedure, but with a twist. Let's say the piano is uniformly 100 cents flat and we plan two pitch raise passes to get everything up to A 440. If you simply pull all the strings up to A 440 target pitch on the first pass, you will end up with the bass maybe 15 cents flat, the tenor 30 cents flat and the treble 45 cents flat - or there 'bouts. Now you are faced with raising the pitch the remaining amount on an unevenly pitched string scale. Not impossible to do by any means, but the larger the pitch raise, the more deviation from uniform and the more guesswork involved in the overpull calculation (i.e. if you pull the 30-cent flat tenor up to pitch plus the 25% overpull, you'll be raising the treble up from about 50 or 60 cents flat - that will tend to make the upper tenor go flatter than A 440. Not that you can't compensate for it, but it sure involves a good bit more guesstimating. Sooooooo, what I do is pull the bass up to A 440 pitch (which will fall to about 15 cents flat), pull the tenor up maybe 10 cents sharp of A 440 (and it too will fall to about 15 cents flat) and pull the treble up about 20 cents sharp, tapering overpull down in the last octave of course (and it too should end up about 15 cents flat). Then you should have all sections of the scale about 15 cents flat and you can do a much more accurate second pitch raise pass (or at least I can). Make sense? It seems to work well for me. Terry Farrell On Feb 4, 2011, at 12:32 PM, Susan Kline wrote: > On 2/4/2011 5:49 AM, Avery Todd wrote: >> >> Besides, if an instrument is THAT flat, I usually just pull it up >> to pitch the first time over anyway. > > That's what I do. Then I use the "wetware" overpull the second time > around, when it can be much less. > > By then, the strings are getting used to sliding over the bearings > again, and one knows if they feel like breaking, as Avery said. > > If it is the age of upright which might have been designed for > A=435, I might pull only to 435 the first time around. I carry a 435 > fork for older (pre-440) pianos which seem reluctant to come up. > > The very first private job I did, while I was still in the course, > was a big old upright way out in the country, painted white, and a > major third low. I cautiously raised it a half tone each pass, came > back in a week or so, tuned it again, came back two weeks later, > tuned it, and it was pretty stable by then. Nothing broke (beginners > luck). I tuned it every six months till I moved away. > > Susan -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20110204/900173d4/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC